High pressure pump



oct. 14, 1958 J, F, MURRAY ETAL 2,855,856

HIGH PRESSURE PUMP Filed Feb. 8, 1951 2 Sheets-Sheet 1 BEAR/N07 HATER/ALf 10 F i 5- 1 z R LL ERMA Z 4 q. 3

OUTLET a Elli E I'IZ'QTE c/Bhn 2 Murray vJames C. Osborne Oct. 14, 1958J. F. MURRAY ETAL 2,855,856

HIGH PRESSURE PUMP.

Filed Feb. 8, 1951 2 Sheets-Sheet 2 BEAR/N6 Mn 01/. 7 179/ 1571 5T'ZTUTE tic #27! F Murray til??? 5 0. Osborne United States PatentOfiice 2,855,856 F atented Oct. 14, 1958 HIGH PRESSURE PUlVIP John F.Murray, Macedonia, and James C. Osborne,

Cleveland Heights, Ohio, assignors to Thompson Products, Inc.,Cleveland, Ohio, a corporation of Ohio Application February 8, 1951,Serial No. 209,984

1 Claim. (Cl. 103126) v This invention relates generally to a highpressure positive displacement pump and more particularly to a highpressure fluid displacement gear pump equipped with slidable bushingshaving an enlarged radial flange arranged to sealingly engage the fluiddisplacement gears of the pump in response to a pressurizing forceintroduced behind the flange and tending to move the bushings toward thepumping chamber. More specifically, the invention relates to a highpressure gear pump having a sectionalized housing with a medial bodymember made of a suitable bearing material sandwiched between endmembers made of a differential material and including a pair of slidablebushings each having a tubular bearing portion adjacent a radiallyextending flange which is interrupted by an eccentrically radiallyextending shoulder located directly adjacent the flange to reduce theeffective face area of the pressure loading surface of the flange towardone side thereof. 1

Heretofore, pressure-loaded pumps in which minimum clearance ismaintained between the gears and the end plates of the pump by bleedinghigh pressure to the back side of the end plates have been deficientbecause an exact balance is not accomplished between the separatingforce and the force tending to maintain a seal relation between the endplates and the gears. It has been found that this separating forcevaries from a minimum at a point adjacent the inlet port to a maximumpoint adjacent the discharge port. The present invention advantageouslyexploits this phenomenom by provision of a slidable bushing of generallytubular construction having a radially extending flange at one endthereof formed with a rotorengaging face at one side of the flange and apressure responsive face on the other side of the flange, the tubularbody portion of the bushing providing a'. bearing means to journal therotor associated therewith.

In order to accomplish a uniform load distribution on the pressureresponsive face of the flange, the axially extending portion of thetubular bushing is interrupted by an eccentrically offset shoulderlocated directly adjacent the flange, the shoulder being generallyannular in configuration and eccentrically arranged to progressivelyreduce the efiective face area of the pressure responsive surface of theflange toward one side thereof. J

An exact balance is thereby approached at any point between the gear andthe bushing, between the load tending to force the bushing away from thegear and the pressure load tending to hold the bushing and the gear incontact. By approaching this balance between the various forcesoperative on the bushing, the tendency of the bushing to twist in thepump housing is eliminated, thereby providing full and evenlydistributed contact between each gear and its associated bushing overthe entire rotor engaging face of the flange on the bushing.

Another feature of the present invention is the provision of a sectionalhousing comprising a plurality of medially spaced sections clampedtogether in firm assembly and including at least two housing sectionsarranged to sandwich an intermediate housing section made of a suitablebearing material and formed to define a pumping chamber receiving therotary fluid displacement means of the pump.

It is an object of the present invention to provide an improved housingstructure for a high pressure pump including a plurality of mediallyspaced sections, the intermediate section being sandwiched between twoend members. and comprising a bearing material whereby a rotarydisplacement means may not only operate in close running clearancewithin a pumping chamber formed in the intermediate member but may alsobe rotatably journaled therein.

Another object of this invention is to provide in a fluid displacementhigh pressure pump an improved slidable bushing and housing arrangement.

Yet another object of the present invention is to provide an improvedbushing for a pressure-loaded gear pump and having a pressure responsiveface varying in cross-sectional area from one side to the other.

Many other features, advantages and additional objects of the presentinvention will become manifest to those versed in the art by makingreference to the detailed description which follows and the accompanyingsheets of drawings on which a preferred form of a high pressure pumpembodying the principles of our invention is shown by way ofillustrative example.

On the drawings:

Figure 1 is a plan elevational view of a high pressure pump provided inaccordance with the present invention;

Figure 2 is an end elevational view of the pump shown in Figure 1;

Figure 3 is a cross-sectional view shown in elevation takensubstantially on line III- -III of Figure 1;

Figure 4 is an enlarged front 'end elevational view of a slidablebushing employed in accordance with the present invention;

Figure 5 is a side elevational view of the bushing shown in Figure 4;and

Figure 6 is a rear end elevational view of the bushing shown in Figure5.

As shown on the drawings:

Upon making reference to the drawings, it will be noted that the pump ofthe present invention is indicated generally by the reference numeral 10and includes a housing 11 made up of three separate sections including afirst end member 11a, an intermediate member 11b and a second end member110, all of the members being medially spaced in generally coaxialdisposition and arranged to be locked together in firm assembly with oneanother by suitable clamping means taking the form in this embodiment ofa plurality of studs 12 secured in the end member Ila as at 13 andpassing through apertured bosses 14 provided in the intermediate member11b and apertured bosses 16 provided in the second end member to receivecastellated locking nuts 17 fixed in a locked posit-ion by means of asuitable locking pin or wire 17a.

In accordance with the principles of the present invention, theintermediate member 11b is made of suitable bearing material such asbronze, or the like and, conveniently forms a composite bearing support,housing structure and pumping chamber for the high pressure pump 10,thereby eliminating the necessity of providing separate bearings and endplate bushings. The use of 3 a pair of bearing portions 2b and 21 toreceive in rotatable journaling relationship the driver and drivenelements respectively of a rotary fluid displacement means.

The rotary fluid displacement means of the present invention is shown ascomprising a driver gear 22 rotatable in the pumping chamber 18 in meshwith a driven gear 23, the driver gear 22 having oppositely extendingaxle portions 245; and 24b and the driven gear 23 having oppositelyextending axle portions 25a and 25b. Thus, the axle portions 24a and 25aof the gears 22 and 23 are journaled in the bearing portions 29 and 21.,respectively of the intermediate member 11b.

On one face of the intermediate member 11!: is provided an annulargroove 2'7 in which is seated a suitable sealing member 22'; such as anO-ring, or the like and an annular flange 29 is also provided so thatthe first end member 11a may be snugly received in abutment with theflange 29 and sealingly engaged by the sealing member 28.

The axle portion 24a of the driver gear 22 is suitably splined to effecta driving connection with a complementally splined stub shaft 3t) andthe end member 11a is suitably bored and counterbored to receive theusual seal structure cooperable with the shaft 3%) and the axle portion240! of the driver gear 22 to close the end of the pump. Thus, a sealcover 31 is received by the largest counterbore portion formed in theend member 11a and carried a thrust ring 32 suitably concaved to providea cooperative bearing engagement with the complementally shaped face ofa shaft flange 3dr: formed on the-stubshaft 30.

The seal strueture-interposed between the end member 1111 and the'axleportion 24a of the driver gear 22 is indicated generally by thereference character S. Since any well known type of shaft seal may beemployed without affecting the principles of the present invention, afurther detailed description of the structure of the seal S is believedto be unnecessary.

It maybe noted that the end member 11a, as well as the end member 110may be fabricated from any conventional form of metal, preferably alightweight metal such as aluminum, or the like.

The end member 110 is provided with a plurality of successively reducedcounterbore portions forming an irregular recess to receive variouselements of the pumping structure. One face of the end member Heengagingly abuts the intermediate member 11b as at 33, the faceterminating inwardly in a first counterbore 34 adapted to receive agenerally figure fl-shaped sealing member such as gasket 36.

A second counterbore 37 of generally figure S-shaped configuration isprovided in the end member 110 and is separated from the counterbore 34by a shoulder 38.

A pair of spaced apart reduced diameter bores 38 and 39, respectively,are provided in the end member He and between the bores 38 and 3% andthe counterbore 37 is provided an eccentrically oflset counterboredrecess 40 of generally S-shaped configuration. Enlarged eccentricallyoffset recesses 38a and 39a, respectively, are formed at the innermostend of the bores 38 and 39 directly adjacent the counterbored recess44).

It will be noted that a radially extending face 41 is provided at thebottom of the counterbore 37 and a second face 42 is provided at thebottom of the counterbored recess 40.

In order to pressure-load the rotary fluid displacement means of thepump provided in accordance with the present invention, a pair ofslidable bushings B are provided to sealingly engage the driver gear 22and the driven gear 23. Although the bushings B for the respectivegears22 and 23 are made of opposite hand, it is believed that the structureof each of the bushings B will be clearly understood from a detaileddescription of one of the members.

Referring particularly to Figures 4, and 6, together with Figure 3, itwill be noted-thatthebushing B comprises a generally cylindrical memberhaving a radially extending flange 42 at one end thereof, one face ofthe flange 42 comprising a gear-engaging face 43 and the other face ofthe flange comprising a pressure responsive surface 44.

A reduced tubular axial extension 46 extends away from the flange 42 andthe peripheral surface of the extension 46 is interrupted by a radiallyoutwardly extending shoulder 47 which is generally annular inconfiguration and which is eccentrically offset with respect to thelongitudinal axis of the bushing B. The shoulder 47 is located directlyadjacent the flange 42, thereby to progressively reduce the effectivearea of the pressure responsive surface 44 toward one side thereof, theamount of area reduction being represented 'by the area included in theplanar face 48 extending transversely of the axis of the bushing B andterminating in the peripheral surface of the extension 46.

It should be noted that the tubular extension 46 is concentricallydispersed relative to the flange 42, thereby greatly facilitatingmachining operations in the production of the bushings B.

In assembling the bushings B in the high pressure pump, the flange 42 ofeach of the bushings B slidingly engages the walls of the pumpingchamber 18 of the intermediate member 11b and is sealingly engaged bythe sealing member 36 in the counterbore 34. It will be noted that'theflange '42 of each 'of the bushings B is generally circular, but isflattened as at 49 to form a mating abutment which prevents rotation ofthe bushings B once located within the pump. The face 43 of each bushingB will sealingly "engagethe sides 'of'the gear'tee'th provided on thedriver gea'r'22 'a'ndthe driven gear 23.

Theflang'e 42'of'the bushing B'also'slidingly engages the shoulder 38"and it should be noted'that the shoulder 38 is made of suflicientlength to provide a clearance behind the pressure responsive surface"44. Thus, the radially extending faces 41 of the counterbore 37 and thepressure responsive surface 44 of each bushing B together form'a'pressure'control chamber P into which pressured fluid maybeintroduced for the purpose of urging the bushings 'B axially intoengagement with the fluid displacement means. Aswill be seen on Figures2 and 3, the end member of the housing 11 may be provided with anaxially extending passageway 50 which places the pressureco'ntrolchamber P in fluid communication with the outlet or thepump 10.

By virtue of the shoulders 47 provided on each'of the bushings B,the'eccentricity of the shoulders 47 results in thedefinition of anirregular exposure area on each of the pressure responsive surfaces 44.

Since fluid pressure in the pressure chamber P is exerted equally in alldirections, the irregular exposure area of the exposed face of thepressure-responsive surfaces 44 will result in a balancing of pressureon opposite sides of the flange 42 so that any twisting couple tendingto twist the bushings B in thehousi'ng 11 will be eliminated. 'In thismanner, contact between'the gear teeth-and the gear engaging face 43 ofeach of the bushings B will be provided.

The pumping-chamber 1'8'formed in the intermediate 'member llb areformed with close tolerances insofar as the outer diameter measurementof the gears 22 and 23 are concerned so that the driver gear 22 and thedriven gear '23 mayoperate'in closerunning clearance with the walls ofthe pumping chamberlS. In this manner, the

intermediate member 11b actually serves to partially journal the fluiddisplacement means through the teeth portions thereof in addition tojournaling the axle por- -tions 24a and 25aof the driver'and drivengears 22 and 23, respectively.

The shoulder '47 on each o-f the bushings B serves to *seat afigure'S-shaped sealing member 51 which, in'this particular embodiment,takes the form of a ring type seal. The sealing'member S1 is received inthe counterbore :recess'40ofthe end member 1 1c, the protrusion-of theshoulder 47 of each of the bushings B into the respective recesses 38aand 39a at the ends of the bores 38 and 39 serving to confine thesealing member 51 so that a seal will be efiected between the bushing Band the end member 110 on both sides of the pressure control chamber P.

In order to initially loadthe bushing B into engagement with the rotaryfluid displacement means, a cap member 53 is located at the end of eachbore 38 and 39 and is placed in abutting engagement with the end of eachof the bushings B, there being a coil spring 54 between each cap member53 and the end member 110 to resiliently load the bushings B intoengagement with the gears 22 and 23.

It will be noted that the axle portion 24b and 25b of each of the gears22 and 23 extend into the bushings B and are journaled for rotationthereby. In order to enhance the full bearing lubrication between theaxle portions 24b and 25b and the bushings B, an undercut annular recess56 is formed in the face 43 of the flange 42 and a pair of diametricallyopposed axially extending blind end grooves 57 are provided for aportion of the length of the bushing B to receive the fluid beingdisplaced by the rotary fluid displacement means as a pressurizedlubricant for the bearing surfaces. A similar provision is made in thebearing portion of the intermediate member 11b including blind endgrooves 57a and the annular recess 56a.

It will be noted that both the driver gear 22 and the driven gear 23 areprovided with hollow shaft portions and the cap members 53 are likewiseprovided with hollow bore passages so that the low pressure of the inletside of the pump may be maintained on the back end of the bushings B inthe locale of the cap members 53 thus precluding the possibility of ahigh pressure pocket forming directly adjacent the back end of thebushing B. To insure the maintenance of a low pressure, the end member110 is provided with a recess 58 which is enlarged at one end to receivea spring-loaded pressure relief valve indicated generally by thereference character R.

It is contemplated that various modifications to the preferredembodiment herein shown and described by way of illustrative exampleonly may be suggested to those versed in the art and it should beunderstood, therefore, that we do not propose to be specifically limitedto the exact pump structure herein disclosed, but desire to embracewithin this patent all structures as reasonably come within the spiritand scope of our contribution to the art.

We claim as our invention:

In a pump, a housing having an inlet, an outlet and a pumping cavity,means defining an axially adjustable bushing having a radially extendingflange at one end with a peripheral surface disposed generallyconcentric with the axis of said bushing and formed with apressure-responsive surface for effecting a liquid seal of the cavity,said bushing being further formed with a reduced axial tubular extensionconcentric with the axis of said bushing at the other end received in acorresponding reduced bore in said housing, a shoulder extendingradially outwardly of said extension and projecting axially from saidflange with a straight uninterrupted peripheral surface, said shoulderbeing offset eccentrically with respect to the axis of said bushing andforming the inner peripheral edge of said pressure-responsive surface toprogressively reduce the face area of said pressure-responsive surfacetowards one side thereof, said housing comprising an intermediate partmade of bearing material in which said pumping cavity is formed, and twoend parts on opposite sides of said intermediate part, one of said endparts being successively counterbored concentrically to receive saidflange, eccentrically to receive said shoulder and concentrically toreceive said tubular extension, whereby critical clearances aremaintained at adjoining parts in concentric relation, means fordirecting pressure liquid to said reduced face area of saidpressure-responsive surface for balancing un equal pressure forces insaid cavity, and a sealing member positioned between said peripheralsurface of said shoulder and said housing, whereby leakage of saidpressure liquid is prevented and said sealing member affords a widerange of manufacturing tolerance at the eccentrically-related portions.

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